The present invention relates to fiber optic cross connects, and more particularly to the packaging for fiber optic cross connects.
The use of optical cross connect (OXC) switching systems are well known in the art for directing a light beam from one optical port in an optical transmission system to another optical port. In a typical OXC, a plurality of input optical fibers, or ports, carry light beams into the OXC. The OXC then directs, or switches, the light beams to their respective plurality of output ports. Many conventional OXCs perform the switching utilizing micromirrors, which are micro-machined on a substrate. The micromirrors are used to reflect a light beam from an input port to a particular output port. In this specification, the words xe2x80x9cinputxe2x80x9d and xe2x80x9coutputxe2x80x9d are used to indicate a direction of travel for a light beam into and out of, respectively, a switch. In reality, the input and output ports can be used simultaneously for input and output, as is the case in bi-directional data transfer.
High port count switches utilizing micromirrors are of high demand in the industry. Such switches require a tight packing density of the micromirrors onto the substrate. Some conventional switches use a digital switching matrix for N input and N output ports with an NxN array of micromirrors. This requires a total of N 2 number of micromirrors. However, this architecture becomes impractical for switch port counts greater than a few hundred.
For conventional OXCS, the optical path from the collimating optics to the micromirror increases with port count and varies substantially. A large distance between collimating optics and the micromirrors requires high optical and manufacturing precision to ensure that the input beam is aligned with the micromirrors.
Accordingly, there exists a need for an improved OXC package which reduces the size of the package while still allowing a high port count. The improved package should also minimize optical loss and crosstalk and also allow a tight packing density of micromirrors. The present invention addresses such a need.
The present invention provides a double fiber optic cross connect (OXC) package. The double package includes an input optical fiber; a substrate with a first surface and a second surface, optically coupled to the input optical fiber; a first cap optically coupled to the second surface of the substrate; a micromirror array optically coupled to the first cap; a second cap optically coupled to the micromirror array; and an output optical fiber optically coupled to the second cap. The first cap, along with a substrate populated with a micromirror array and a set of side walls, form at least one volume which is preferably hermetically sealed. This volume is further enclosed by the second cap with another set of side walls.